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Search: id:A026769
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| A026769 |
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Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; T(2,1)=2; for n >= 3 and 1<=k<=n-1, T(n,k)=T(n-1,k-1)+T(n-2,k-1)+T(n-1,k) if 1<=k<=(n-1)/2, else T(n,k)=T(n-1,k-1)+T(n-1,k). |
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30
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| 1, 1, 1, 1, 2, 1, 1, 4, 3, 1, 1, 6, 7, 4, 1, 1, 8, 17, 11, 5, 1, 1, 10, 31, 28, 16, 6, 1, 1, 12, 49, 76, 44, 22, 7, 1, 1, 14, 71, 156, 120, 66, 29, 8, 1, 1, 16, 97, 276, 352, 186, 95, 37, 9, 1, 1, 18, 127, 444, 784, 538, 281, 132, 46, 10, 1, 1, 20
(list; table; graph; listen)
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OFFSET
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1,5
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FORMULA
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T(n, k) = number of paths from (0, 0) to (n-k, k) in directed graph having vertices (i, j) and edges (i, j)-to-(i+1, j) and (i, j)-to-(i, j+1) for i, j >= 0 and edges (i, i+h)-to-(i+1, i+h+1) for i >= 0, h>=1.
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CROSSREFS
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Sequence in context: A026758 A130523 A034363 this_sequence A060098 A161492 A034781
Adjacent sequences: A026766 A026767 A026768 this_sequence A026770 A026771 A026772
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KEYWORD
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nonn,tabl
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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